It is well known that in certain patients epileptic seizures consistently originate from a single location within the brain. When a primary epileptogenic region or seizure focus is suspected, some form of monitoring by implanted electrodes may be performed during which time the electrodes are connected to recording instruments such as an electroencephalograph (EEG) machine. Additionally, in some patients, intracranial electrical stimulation using implanted electrodes is performed to map regional brain function as a precursor to surgical excision of the epileptogenic region. During the mapping procedure, the stimulation will often induce seizures or seizure-like after discharges from the epileptogenic region.
Electrical stimulation therapy is an alternative to resective surgery. To be most effective in using electrical stimulation as a therapy, the electrode location(s) and electrical pulse parameters must be adapted to each patient. Existing devices for electrical stimulation therapy, such as the Cyberonic's NeuroCybernetic Prosthesis System and the Medtronic Activa System, have the capability for adjusting stimulation parameters only after surgical implantation of the therapeutic device. This means that considerable expense and patient associated risks are incurred before it is known that the device will be therapeutic or how well it will function after it is implanted.